Lactose intolerance is the inability to digest lactose, the sugar found in milk and dairy products, and affects approximately 25 percent of American adults, although the rate varies according to race and age. The intolerance, which can cause gas or diarrhea, varies in severity, so most people are still able to consume at least some dairy. However, US demand for lactose-free milk has increased by 20 percent per year since 1997, the researchers claim.
They examined differences in flavor and overall sensory perception of various lactose-free milks available commercially in the US and compared them to perception of regular milks. The tasting – which was carried out by a trained panel of nine sensory analysts in blind tastings – found that there were “significant differences” between the lactose-free and regular milks. A parallel survey involving consumers was carried out, with similar results.
“While lactose-free milks have addressed the needs of lactose intolerant consumers, there still needs to be a strong similarity to regular milk for the consumer to purchase the product and be satisfied,” the researchers wrote.
Commercially-produced lactose-free milk is made by breaking down lactose into glucose and galactose by a process called enzymatic hydrolysis. The resulting milk contains about 0.25g of lactose per 100ml, compared to 4-6g of lactose in regular milk, and tastes much sweeter. The lactose-free varieties were also described as having more chalkiness, less freshness, more cooked flavors and higher viscosity.
“These results can be very useful to the dairy industry to get a better understanding of the differences between regular milks and lactose-free milks in order to produce better tasting lactose-free products, and to educate the lactose-intolerant consumers about the benefits of UP [ultrapasteurized] lactose-free milks,” wrote the researchers.
More than 90 percent of Asians and Native Americans are lactose intolerant, compared to around 75 percent of African Americans, 50 percent of North American Hispanics and about ten percent of European Americans.
Source: LWT - Food Science and Technology (2009)
Sensory characteristics of commercial lactose-free milks manufactured in the United States
K Adhikari, LM Dooley, E Chambers, N Bhumiratana